Cotton is wicking.
It is one of the most wicking fabrics there is.
Tech fabrics do not wick - though most people think it's the other way around.
Cotton is also one of the most breathable fabrics there is.
Wicking is the fabrics ability to absorb moisture. Cotton does it better than most other fabrics. What it also does is hang onto the moisture.
Tech fabrics do not absorb moisture, they are woven fine enough with big enough gaps in the weaving to allow moisture to pass through.
Most cotton T's around probably only cost £1 max to produce - I was buying mine at 99p each and they weren't the cheapest. This is the sort iof quality of T that you'd get as a race T.